In recent years, due to advantages such as low invasiveness in relation to the subject, there has been a significant increase in techniques performed by inserting a funicular insert instrument configured by a narrow, funicular member into the body. These insert instruments include catheters as well as guide wires that are introduced together with catheters, etc. In this specification, these and other funicular insert instruments are hereinafter referred to as “wire(s)”. Because wires generally absorb more X-rays than the human body, in X-ray images, they are observed as relatively clear black, narrow lines.
One example of a surgery in which wires are used is catheterization under X-ray fluoroscopy. In catheterization under X-ray fluoroscopy, a catheter is inserted into the body from an artery of the femoral region, etc., and the catheter is guided to the affected area while referring to an X-ray fluoroscopy image (moving image) displayed in real time to perform treatment.
An X-ray imaging apparatus used in catheterization under X-ray fluoroscopy irradiates X-rays for fluoroscopy to a subject into whom a catheter has been inserted, detects X-rays that have penetrated the subject, and based on the detection results, forms and displays a Real time rendering movie depicting the interior of the subject. Moreover, the X-ray imaging apparatus is configured to be able to change fluoroscopy conditions, including the X-ray dosage during fluoroscopy of the subject, based on information from input operations, and when the X-ray dosage is raised, a finer Real time rendering movie is displayed as a result. In a finer Real time rendering movie, it is possible to make the tissues inside the subject, including the blood vessels, easier to view (e.g., Patent Document 1).
In catheterization under X-ray fluoroscopy, the operator must guide the catheter to the affected area through an appropriate path through the blood vessels, which are stretched in all directions like a maze, to the affected area. Operations for doing so are performed by manipulating the part of the catheter that is outside the body. Therefore, catheterization under X-ray fluoroscopy requires expert skill.
When inserting a catheter into a desired branch at a desired bifurcation of the blood vessels, or when passing a constricted portion, first, the apical part of the catheter is inserted into the path. To do this, the operator performs very subtle operations, including appropriately combining operations such as advancing, retracting and twisting the catheter. Furthermore, if the catheter is advanced while the apical part is not appropriately inserted into the path, complications such as puncturing of the blood vessel may occur.
Moreover, when appropriately inserting the apical part of the catheter into the path, in order to make the branch or constricted portion of the blood vessel easier to observe, it is possible to confirm the position to which the guide wire should be advanced by displaying a finer X-ray fluoroscopy image. To display a finer X-ray fluoroscopy image, it is possible to occasionally supply a contrast agent from the catheter and observe the image of the contrast agent that appears for only a few seconds to confirm the position to which the guide wire should be advanced. However, because contrast agents impose a burden on the kidney function of the patient, the quantity used is limited, and it is not possible to continuously use a contrast agent during operations to insert the apical part of the catheter. Moreover, it is possible to display a finer X-ray fluoroscopy image by raising the X-ray dosage during fluoroscopy of the subject. However, in catheterization under X-ray fluoroscopy, the act of continuously irradiating the subject with large dosages of X-rays contradicts the imperative to minimize the amount of exposure of the subject.